I have been to Gettysburg more times than I can count. I actually stopped counting about ten years ago, because it was just getting silly. But as a byproduct of these many visits I have some incredible mental images tucked away.

Dawn, looking across the fields from Seminary Ridge towards Cemetery ridge as a morning mist writhes across the whole silently, making the granite men of countless monuments seem alive. Dusk, from near the summit of Little Roundtop looking west towards the Devil's Den. Often I have been the only person in sight during one of those magic moments that allow my mind's eye to take flight through time.

Two years after I started teaching at West Point, I was on another part of the field, and my fellow professors and I were leading almost 150 cadets from West Point around the section where the initial fighting of the first day took place. As you may have discerned, I believe that stories are what makes history come alive. Accordingly, I had been tossing and turning for weeks wondering how to make this trip to hallowed ground memorable to these young future-officers. I knew I could tell a good story, and by this point I knew I was a good teacher, but I wanted to add a little something more. That is when I remembered my friend Mike Riley.

Mike is, well, in the simplest of terms he is a reenactor. But I never thought that word appropriate to him, or the dozen-or-so others like him. Mike is so much more. He is, as I call it, a living biographer. In other words, Mike does not just wear the uniform of a particular unit, or even a particular (though unknown) lower-level officer. When Mike is on the field, usually between Seminary Ridge and McPhereson's Ridge, Mike just simply is Union General John F. Reynolds, Commanding Officer, 1st Corp, Army of the Potomac.

A native of Lancaster, Pennsylvania (home of the original Reynolds) Mike is, without any doubt in my military mind, the single most educated and expert human alive on everything there is to know about General Reynolds. Yes, he knows a lot of other things as well, but in this one thing nobody on the planet knows more than Mike. What is more, somewhat spookily, he looks very much like Reynolds did in 1863. Given the critical role that this general played in the battle, and the dramatic nature of his story, I arranged for Mike to be at a particular place, at a particular time, as I led the cadets around the battlefield.

I do not like to spoil stories. But, sorry, here is a spoiler.

Reynolds was the commander of the whole "right wing" of the Army of the Potomac. That means that he had his own Corps, plus two others that would do what he said. Most significantly, he was the general who, at the critical moment on the first day, arrived on the battlefield-to-be and agreed with the cavalry officer commanding the troops already in Gettysburg. Essentially he agreed to the idea: Yes, this is where we will fight.

Reynolds had literally galloped to the sound of the gunfire that morning, the First of July, as he approached Gettysburg from the south. As he did so he left his infantry a few miles behind. It would be a good while before his initial forces could get to the critical point, but Reynolds knew that he had to see the ground himself first. These precious minutes gave him time to see the terrain, to confer with that cavalry general who was holding the land and to understand the enemy situation. This meant that when his leading infantry formations did arrive, he already had an appreciation of the situation. He had also sent messengers off for the other Corps under his command as well as to General Meade. Then, when his leading formations arrived, he threw in his men at the vital point and they crushed the first serious rebel attack. But in the instant of his greatest success, he was killed, right behind the front line as he urged his men forward.

Almost every single one of the men and women I was teaching that day would fight in Iraq or Afghanistan or both. Many of these cadets with me that day -- by then young lieutenants and captains -- would be wounded in the wars of the past decade. Some who walked through the woods and fields of Gettysburg that day in 2000 would die on foreign fields far from home. But we did not know that then. What I knew was that this walk through Hebst's Woods was more than history. This was about teaching officers-to-be their profession, and what could be expected of them. See, for us history is sometimes more than just the stories.

As we came out of the woods where the Confederates had attacked and the Union had countered with an attack of their own, Mike was there, standing beside a granite plinth. He was, every inch, General Reynolds. I introduced him that way as well. And then Mike started telling the story that I had laid the groundwork for over the preceding half-hour of walking and talking. He talked, in the first person, about Reynold's background. He told them how he came from Lancaster, Pennsylvania, and how he himself had attended West Point. He talked about his time as a cadet, wearing the grey uniform of West Point, and then his time as a young officer. Then he skipped forward to the Civil War and explained Reynold's rise through the ranks, until at this point he was commanding a Corps. And only then did he explain (I had kept it quiet too) that he was standing at the spot where Reynolds, the real Reynolds, was killed that July morning.

Civil War reenacting has had its ebbs and flows over the years. And as almost any reenactor will admit, it is both an expensive hobby and one that attracts more than a few stares. But as an academic historian let me tell you, for the most part I think the folks who take this up as a hobby are fun people to be around, and in not-a-few cases, the reenactor can be an invaluable resource, even for somebody like me.

I may read between 80 to 100 books a year, cover to cover, depending upon the situation. But then that is a part of what is expected of me as an academic. But I do not have the time to read, in detail, about every single thing that might interest me. So, I have to make choices about what I will just have to leave aside. This is made slightly easier because like all academics, I keep tabs on who is an expert in what topic. In the case of some aspects of the Civil War, I keep tabs on some reenactors, because they are scholars in their own right in some particular topics. So, if I need to know more about something that I know touched on Reynolds's life, I know that I need only contact the world's foremost expert on the man, my friend Mike.

And that is a part of what I love about the field of history. You do not need to have a fancy degree or expensive lab equipment to do solid history. It is not required, by the discriminating consumers of history, that you pass some sort of bar exam before you present the findings of your research. All you need is a brain, some time, a healthy dose of skepticism, and pen and paper. Then, so long as you follow the well-established rules, what you publish will be judged on its merits.

Importantly, the the rules are not that hard: Look at all the sources available for your topic. Understand the biases of each source and judge them accordingly as you use them. Look at your own biases, and explain those and how they might affect you. Then document in your writing (usually through footnotes or endnotes) exactly where each and every statement of fact came from, and why you judge it a "fact" and not just an "opinion." One need only adhere to some simple format rules for documentation, but that is not onerous. The key point is it must be possible for others to replicate your research. That is all. Really, all of this is little more than what most of us learned in high school.

I admit, advanced degrees in history do make things easier. You learn not what to think, but how to think, and how to be skeptical and how to identify biases in yourself and your subjects. And you also get a sound basis in the general field of history and how those parts fit together. But that is nearly all there is to it, and with a will, even this can be self-taught.

Take, for example, one of my favorite books of the Civil War, The Story The Soldiers Wouldn't Tell, by Thomas P. Lowry. The book could also be titled, The Story the Historians Wouldn't Tell, but Lowry was too polite for that.

The book is about sex in the Civil War, and no small part of it deals with the inevitable venereal diseases that afflicted soldiers of all ranks. Lowry happens to be an M.D., who during the course of his own research into things historical and medical, kept running across materials about VD rates, and accounts of wayward chaplains and how the armies dealt with things like prostitution. He then focused on that, and finally he combined all of it into this amusing and fascinating book. In my opinion, only an M.D. could have written a book like this.

But what really makes it respectable is that he followed all the rules. His book is completely documented (and, somewhat amusingly, illustrated), and is one of those things that I loan to students for a day when their interest seems to be waning. Lowry helps me remind them, these were men and women, like you and I, with all the same faults and flaws and sometime flights of unimaginable courage.

So if you go to Gettysburg, this weekend, you need to brace yourself. But the same applies to any of the 150th Anniversary battle reenactments that will be occurring over the next 22 months. Do not shy away from the reenactors, because almost all of them are passionate repositories of information who can potentially bring the period to life for you. This is especially true if you are bringing kids. Reenactors are not without flaws, of course, and not all are created equal. But a little discrete questioning over a pint will help you find the best ones at any encampment. So dig in, and enjoy.

Now, for the last issue of the day. I was going to write about this topic at length, but decided talking about history and historians and reenactors fit better here. So now, having used up my space, I will make this short.

The commanding general of the Army of the Potomac was a guy named Hooker. About seven weeks earlier he had been absolutely thrashed when Lee and Stonewall Jackson mesmerized him and then gobsmacked the whole Army. But up until now he has been doing okay, if acting a little gun-shy. He has increasingly been getting annoyed, however, by how his boss (a general back in Washington named Halleck) and the President, are getting into his business and telling him what to do. Finally, Hooker decided to push back. He offered his resignation, apparently in the sure, self-confident opinion that this act of false deference would get the President and Halleck to back off and let him do his job without their interference.

As a bluff, it was a profoundly obtuse effort. In essence, Hooker pulled a Homer. ("DOH!") Instead of backing off when his general would not do what he wanted, President Lincoln accepted Hooker's resignation, and immediately appointed a reluctant Major General named George Gordon Meade, as the new Commander of the Army of the Potomac. Workmanlike, steady, dependable, if somewhat hot-headed at times. That happened today.